Comparative pathogenesis of two spodopteralittoralis nucleopolyhedro virus isolates against culex pipiens larvae

Viruses represent an important class of pathogens, and the most common viruses of mosquitoes are baculoviruses, which is considered as one of the most promising bioinsecticides. We estimated LC50 values of two local nucleopolyhedrovirus isolates from Spodopteralittoralis larvae (SLNPV) from two localities in Egypt; Giza and Cairo governorates; and their effect on the midgut region of third larval instar of Culex pipiens larvae after 6, 24 and 48 hours. LC50 values for Giza SlNPV and Cairo SlNPV were (1.7 X 105 PIB/ml and 2.2 X 1010 PIB/ml.) respectively. In this investigation, an ultrastructure study, using semi-thin sections and electron micrographs was carried out to demonstrate the effect of the two isolates Giza SlNPV and Cairo SlNPV on the third larval instar of Cx. pipens. Treatment with Cairo SlNPV showed changes in the epithelial cells which returned back to its normal shape. Data reveals that Giza SlNPV was more efficient for control Culex pipiens larvae than Cairo SlNPV, and it can cause death to larval stage at 48h post infection with dramatic changes in the midgut layer, which makes this baculovirus as effective as insecticides, but in a safer form, and can be successfully included in the integrated pest management.